Circuit breaker with spring biased pivot for movable contact members



June 1954 T M. COLE ET AL 2,681,396

CIRCUIT BREAKER WITH SPRING BIASED PIVOT FOR MOVABLE CONTACT MEMBERS Filed May 1, 1952 5 Sheets-Sheet l 7 INVENTORS v '7' THOMAS M. (045,

. 75 4 M. a/z/srn/seu *ffi 24 m June 15, T M COLE ET AL 2,681,396

CIRCUIT BREAKER WITH SPRING BIASED PIVOT FOR MOVABLE CONTACT MEMBERS Filed May 1, 1952 5 Sheets-Sheet 2 IN VEN TORS June 15, 1954 T, M. COLE ET AL 2,681,395

CIRCUIT BREAKER WITH SPRING BIASED PIVOT FOR MOVABLE CONTACT MEMBERS Filed May 1, 1952 5 Sheets-Sheet 3 Z 5 FIE-1,9. 55 m5 ms {05 O l J 75.15.

90 60B 72 /02 as 92' Z55 fog [3/00 9 lll l lllllll 76 M 72 708 I INVENTORS /00 A; 96 l;;ll|| 92 BY 1 A94 g4 H16 ,fixa/evsKs June 1954 T. M. COLE ETAL 81,396

CIRCUIT BREAKER WITH SPRING BIASED PIVOT FOR MOVABLE CONTACT MEMBERS Filed May 1, 1952 5 Sheets-Sheet 4 fZC IOC

FIG. 22.

June 15, 1954 T, M. COLE ET AL 2,681,395

CIRCUIT BREAKER WITH SPRING BIASED PIVOT FOR MOVABLE CONTACT MEMBERS Filed May 1, 1952 5 Sheets-Sheet 5 /oo x H5. 32.

Patented June 15, 1954 2,681,396 CIRCUIT BREAKER WITH SPRING BIASED PIVOT FOR MOVABLE CONTACT MEMBERS Thomas M. Cole, Harrison, N. Y., and Paul M. Christensen, West Orange, N. 5., assignors to Federal Electric Products Company, Newark,

N. 3., a corporation Application May 1, 1952, Serial No. 285,418

41 Claims.

lEhe present invention relates generally to automatic circuit breakers and in particular to circuit breakers of the type in which an actuator is pivotally carried by the movable contact member and is latched thereto under the control or a current-responsive device for the manual opera tion of the circuit breaker to open and close it.

Circuit breakers of the general type to which the present invention relates are shown in U. S. Patent No. 2,209,352, issued on an application filed by Joseph Sachs and Paul M. Christensen, one of the joint inventors of the present invention, and is also shown in U. S. Patent No. Re. 23,188, issued on an application filed in the name of Harold A. Humpage, as well as in several patent applications assigned to the assignee of the present application, one or more of which applications will be subsequently referred to as the description proceeds.

As indicated in said Patent No. 2,209,352, provision should be made for resiliently acting on the movable contact member for assuring the required contact pressure for proper engagement between the companion contacts of the circuit breakers when the breaker is closed and a resilient link, indicated at 18, in said Patent No. 2,209,352, which connects the handle to the actuator, being provided for that purpose. Pursuant to the present invention, it is unnecessary to provide a resilient link between the handle and the actuator for the movable contact member and it is also unnecessary to resiliently mount the contacts as disclosed in U. S. Patent No. 2,209,351 issued on an application filed by Joseph Sachs. The elimination for requirement of a resilient link between the handle and the releasably latched actuator is obviated pursuant to the present invention whereby the connection to the handle and the actuator can be constituted by a rigid link, if desired, and a resilient mounting of the contacts is not required. In the copending U. .8. application Ser. No. 221,429, filed April 1'7, 1951, by Paul M. Christensen, a joint inventor of the present invention, and assigned to the assignee of the present application, the aforementioned resilient link is also obviated and the required contact pressure is obtained by providing a floating pivot for the movable contact member in conjunction with spring means connected between the manually operable handle of the circuit breaker and the movable contact mem-- ber to resiliently bias the latter toward the stationary contact when the circuit breaker is closed. Pursuant to the present invention, the means which resiliently acts upon the movable contact member is associated with the mounting means for the movable contact member.

Pursuant to the present invention and an object thereof, provision is made for a resilient pivot mounting for the movable contact member which provides for limited bodily movement of the movable contact member and which mounting also serves to bias the movable contact member to resiliently press the latter against the stationary contact for proper contact pressure when the circuit breaker is closed to compensate for wear of the contacts, or for other inequalities.

Another object is to provide a resilient pivot mounting which incorporates means to calibrate the circuit breaker.

Another object is to provide a resilient pivot member for the movable contact member.

it is well known that the various materials used to fabricate the contacts of a circuit breaker, for example tungsten, are subject to oxidation which tends to reduce the current conductivity of the contacts. Therefore, a further object oi the present invention is to provide for a sliding or wiping motion of the contacts, after the initial contact has been made, in order to remove the film resulting from said oxidation.

The above and other objects, features and advantages of the present invention will be more fully understood from the following description considered in connection with the accompanying illustrative drawings.

In the drawings:

Fig. 1 is a side View of a circuit breaker, pursuant to an embodiment of the present invention, a portion of the casing being removed, and the circuit breaker being in the circuit making condition thereof;

Fig. is a fragmentary sectional view taken on the line 22 of Fig. 1;

Fig. 3 is a view similar to Fig. 1, the circuit breaker being shown in the open position thereof;

Fig. 4 is a fragmentary sectional view taken on the line ld of Fig. 3;

Fig. 5 is a fragmentary sectional view taken on the line 5--5 of Fig. 4;

Fig. 6 is an end view of the circuit breaker, on a reduced scale, taken in the direction of the arrow 6 in Fig. 1;

Fig. 7 is a View similar to Fig. 1, illustrating another embodiment of the invention;

Fig. 8 is a fragmentary sectional view taken on the line 8--8 of Fig. 7

Fig. 9 is a view similar to Fig. '1, the circuit breaker being shown in the open condition thereof;

Fig. 10 is a fragmentary sectional view on the line ill-15 of Fig. 9;

Fig. 11 is a fragmentary sectional view on the line H--H of Fig. 10;

Fig. 12 is an end View, on a reduced scale, as seen in the direction of the arrow I2 in 7;

13 is a view similar to Fig. 1, and illus P trates another embodiment of the present invention;

Fig. 14 is a fragmentary sectional view taken on the line l4-M of Fig. 13;

Fig. 15 is a fragmentary sectional view taken on the line [5-15 of Fig. 14;

Fig. 16 is a view similar to Fig. 13 showing the circuit breaker in the open condition thereof;

Fig. 17 is a fragmentary sectional view on the line lll'i of Fig. 16;

Fig. 18 is a sectional view on the line Iii-l8 of Fig. 17;

Fig. 19 is an end View of the circuit breaker, on a reduced scale, taken in the direction of the arrow IS in Fig. 13;

Fig. 20 is a view similar to Fig. 1, illustrating another embodiment of the present invention;

Fig. 21 is a fragmentary sectional view taken on the line iii-2| of Fig. 20;

Fig. 22 is a fragmentary sectional view taken on the line 22-22 of Fig. 21;

Fig. 23 is a view similar to Fig. 20 showing the circuit breaker in the open condition thereof;

Fig. 24 is a fragmentary sectional view taken on the line 24--24 of Fig. 23;

Fig. 25 is a fragmentary sectional view taken on the line 25-25 of Fig. 24;

Fig. 26 is an end view, on a reduced scale, taken in the direction of the arrow 26 in Fig. 20;

Fig. 27 is a view similar to Fig. 1, illustrating another embodiment of the present invention;

Fig. 28 is a fragmentary sectional view taken on the line 28-48 of Fig. 27;

Fig. 29 is a fragmentary sectional view taken on the line 2929 of Fig. 28;

Fig. 30 is a view similar to Fig. 27 showing the circuit breaker in the open condition thereof;

Fig. 31 is a fragmentary sectional view taken on the line 31-43! of 30;

Fig. 32 is a view similar to Fig. 29 and illustrates a modified casing recess;

Fig. 33 is an end view, on a reduced scale, taken in the direction of arrow 33 in Fig. 27;

Fig. 34 is a fragmentary view of the pivot portion of the circuit breaker illustrated in Fig. 27 and illustrates a pivot member having provision for calibrating the circuit breaker;

Fig. 35 is a fragmentary sectional view taken on the line 35-35 of Fig. 34; and.

Fig. 36 is a perspective view of a resilient member utilized in the embodiment illustrated in Fig. 27. I

Referring now to the drawings in detail, the various circuit breakers which illustrate the various embodiments of the present invention, each comprises a two-part insulation casing having complementary molded parts it! and 12, in which the terminals it and i6, and the circuit breaker mechanism are mounted, as described, for example, in U. S. application Ser. No. 127,433, filed November 15, 1949, by Thomas M. Cole, now U. S. Patent No. 2,647,186 dated July 28, 1953, a joint inventor of the present invention, and in U. S. application Ser. No. 217,162, filed March 23, 1951, by both the joint inventors hereof, now U. S. Patent No. 2,642,509 dated June 16, 1953, both of which applications are assigned to the assignee of the present application. It will be understood that the two casing parts it and 12 are held together by bolts or other suitable means passing through the openings ii; in casing part [0 and similar openings in casing part 12 which register with openings it when the two casing parts are in assembled relation. As here shown, the terminal member i6 is in the form of the plug-in type, as described in the abovementioned U. S. Patent No. 2,647,186. It will be understood that this is not essential to the present invention but, on the contrary, a different type of terminal member may be provided in place thereof.

The stationary contact 20 is carried by the terminal member It in a position within the easing to be engaged by the movable contact 22 carried by the movable contact member 2 3. Said movable contact member is mounted for pivotal movement between the casing parts I i) and 12, to and from the circuit closed condition, illustrated in Figs. 1, 7, 13, 20 and 27, in which contact 22 engages the stationary contact 29, and to and from the circuit open position, illustrated in Figs. 3, 9, 16, 23 and 30, in which said movable contact 22 is shown disengaged from said stationary contact 25. This movement may be accomplished manually by the handle 26 which is connected to the channel-shaped actuator 28 by a link 30, which is pivotally connected at one end thereof to a lug 32 provided on the handle 26 and at its opposite end is pivotally connected to said actuator, as at 34. The actuator 28 is pivotally mounted on the movable contact member, as indicated at 36, and is operatively connected to the movable contact member for moving the latter under the control of the current-responsive latch 33 which, as here shown, includes a bi-metallic strip 49 and an electro-magnet device 52, by which said actuator is releasably latched to the movable contact member, as described in the above mentioned Patent No. Re. 23,188.

It will be understood that, as illustrated in Figs. 1, 7, 13, 20 and 27, when the handle 26 is in the on or circuit closed position thereof, and the actuator 23 is latched to the movable contact member 22 by engagement with the outer end of the bi-metallic strip 68, as shown, relative pivotal movement between the actuator and the movable contact member is prevented and contact 22 is in engagement with contact 28. In this position the link 33 which, pursuant to the present invention, may be a rigid link, and the actuator 23 are in over-set toggle condition and, in order for the circuit breaker to open either automatically, i. e. pursuant to the flexing of the bi-metallic strip it, either upon heating thereof or by the attraction of the strip to the electromagnet armature 22, the toggle must be broken and this can take place either by movement of the handle 26 to its circuit open. position (Figs. 3, 9, 16, 23 and 30) manually or by release of the end it of the actuator by the bi-metallic strip 49, when the circuit breaker trips upon overload or other predetermined load conditions. The openin of the circuit breaker when the latch 38 releases the actuator 28 is efiected by the spring 26, which is engaged at one end thereof with 2, lug 28 provided on the handle 26, and at its other end thereof is engaged with a lug 53 provided on the movable contact member 24.. t will be understood that spring 16 biases both the movable contact member and the handle to the circuit open positions thereof so as to move both the handle and the movable contact member to said positions, as illustrated in Figs. 3, 9, 16, 23 and 30, when the latch 3 disengages actuator 22. It will also be understood that even though the handle 26 is held in the on" position, the spring 66 is effective to open the circuit breaker when the latter is tripped, i. e. when the latch 36 disengages actuator 23.

A feature of the present invention is the pro vision of a resilient pivot mounting for the movable contact member of the circuit breaker in order to permit both for a limited bodily movement of the movable contact member and for biasing the movable contact 22 toward the stationary contact 20 in the closed circuit position of the movable contact member, in order to provide the proper pressure between said contacts when they are engaged, or to compensate for wear or other inequalities in the various cooperating parts of the circuit breaker. Referring now to Figs. 1 through 6 of the drawings in detail, which figures represent one embodiment for accomplishing this purpose, the pivot 52 for the movable contact member 24 is constituted by a resilient member preferably formed of spring wire. At each end thereof the pivot 52 is provided preferably with a metal sleeve 54 which is in the form of a truncated cone, the sleeves being mounted in the complementary tapered bearing recesses 56 and 58, respectively, of the casing parts ill and 12, respectively. In this connection it will be noted that bearing recesses 56 and 58 are larger than the sleeves 54 to per-- mit for limited movement of the pivot ends therein, from the position thereof illustrated in Fig. 4, which represents the condition of the pivot 52 in the circuit open condition of the circuit breaker, to the position illustrated in Fig. 2, wherein the pivot bowed downwardly in the circuit making or closed condition of the circuit breaker. It will be understood that in the overset toggle condition of the link 3% and the actuator iii, a component of force of said toggle will tend to urge the movable contact member in a downwardly direction in order to bow the spring wire pivot 52, whereby the portion Gil of the movable contact member, in which the pivot 52 is engaged, will be moved bodily relative to the casing parts, from the position thereof illustrated in i to the position thereof illustrated in Fig. 2. As previously indicated, said downward movement of the movable contact member is facilitated by the tapered mounting recesses 56 and 58 which freely permit the center of the spring pivot 52, which carries the movable contact member 24, to flex or bow downwardly. Furthermore, it will be apparent that in said flexed or bowed condition thereof, the pivot member 52 is tensioned and will resiliently urge the movable contact member in an upward direction for resiliently biasing the movable contact 22 against the stationary contact 28 to provide the desired contact pressure. Furthermore, it will be readily apparent that said tensioning of the pivot 52 will also result in such bodily movement of the pivot carrying portion fill of the movable contact member as may be required to effect the desired contact pressure.

Referring now to Figs. 7 through 12 of the drawings in detail, there is illustrated another embodiment of a resilient pivot mounting for the movable contact member, which embodiment is the best mode presently contemplated by us of carrying out our invention. Pursuant to the present embodiment, the spring wire pivot 52 is replaced by a resilient pivot 62 constituted by a tightly coiled spring. The spring ends are mounted in bearing recesses 64 and 66 provided in the companion casing part [0A and IZA, respectively. lit will be noted that said bearing recesses are each provided with a lower surface portion 68 which is inclined downwardly to permit for the downward bowing or flexing of the coiled spring pivot 62, in the closed or circuit making condition of the circuit breaker, as illustrated in Fig. 8. As previously indicated in connection with the spring wire pivot 52, when the circuit breaker toggle is in the over-set condition thereof, there will be a component of force which tends to urge the portion A of the movable contact member 24A, which carries the pivot 62, in a downward direction whereby to downwardly flex or bow the pivot 62 from the condition thereof illustrated in Fig. 10, which represents the open or off condition the circuit breaker, to the condition illustrated therein in Fig. 8, in the closed or circuit making condition of the circuit breaker. The downwardly inclined portions $3 of said bearing recesses 64 and 66, permit said flexing of the pivot E52 whereby to bodily carry said portion 50A of the movable contact member 24A. downwardly from the position thereof in Fig. 10 to the position thereof illustrated in Fig. 8. The flexed pivot 82, being tensioned, will resiliently urge the movable contact member 2%. in a direction to move the portion 515A toward the original position thereof, whereby to resiliently bias the movable contact 22 against the stationary contact 20 to provide the required contact pressure.

Referring now to Figs. 13 through 19 or" the drawings in detail, there is illustrated an additional embodiment of a circuit breaker provided with a resilient pivot mounting, in which the pivot is provided with the additional function of calibration for the circuit breaker. In the previously described embodiments, the movable contact member is provided with a peripherally interrupted aperture it to provide for the calibration thereof by the insertion therein of a tapered member as shown, for example, in the above mentioned U. S. Patent No. lot- ,186. However, in the present embodiment, the pivot includes the calibration device, and is of the type illustrated and described in our copending U. S. Patent No. 2,642,569. lihe calibration device for the present embodiment comprises a pivot constituted by the screw 52 having a tapered part 14 and includes the nut '56. The tapered part i l engages the movable contact member 2 313 in an opening '28 adjacent to and laterally in communication with recess fill the movable contact member so that by turning the screw it in a clockwise direction, vi wing Fig. 13, part 32 of the movable contact member may be moved or displaced in a counter-clockwise direction (viewing Fig. 13), with respect to the other part M of the movable contact member, to which the latch device 333 is secured, whereby to provide the desired degree of overlap of part MB of the actuator 233, thus to predeterininev the amount of flexing of the bi-metallic strip 5:53 in actuatorreleasing direction, in response to the load condition for tripping the circuit breaker.

The casing part IQB is provided with an opening 83 which extends therethrough, said opening being enlarged as at so at the inner surface of said casing part. The casing part EEB is pro-- vided with a recess 92 havin an enlarged portion 9d, at the inner surface oi said casing part. Resilient bearings es and as for the pivot screw F2 are disposed in the opening 83 and in the recess 92, respectively. More specifically, it will be noted that the opening 86 is provided with a shoulder as at lilil, and the recess s2 is pro vided with a shoulder as at 532. Each of said resilient bearings, as here shown, comprises a band of metal, nreferably spring steel, which is spirally wound. The resilient bearing 96 is disposed in the enlarged aperture portion to and abuts the shoulder hit. The resilient bearing as is disposed in the enlarged recess portion 9% and abuts the shoulder Hi2. It will be understood that when said resilient bearings are inserted into said casing parts, they are partly compressed whereby they are retained in position by their own tension. It will be noted from Figs. 14 and 17 that the pivot member 12 extends through each of the spring bearings, being mounted in the centers, respectively, of said bearings. Fig. 1'7 indicates the condition of the spring bearings, in the open or off position of the circuit breaker, and it will be noted that in said condition, the spring bearings are substantially relaxed. Figs. 14 and 15 illustrate the condition of the spring bearings in the closed or circuit making condition of the circuit breaker. As described in connection with the previously described embodiments, the over-set toggle condition of the link 30B and the actuator 283 in the circuit making condition of the circuit breaker provides a component of force which tends to move the portion 60B of the movable contact 24B, in which the pivot screw '12 is mounted in a downward direction from the position thereof illustrated in Fig. 17, to the position thereof illustrated in Fig. 14. Said bodily movement of the movable contact member results in the compression of the spring bearings, as illustrated in Figs. 14 and 15.

Fig. 18illustrates the position of pivot 12 in the open condition of the breaker, said position also being shown in broken line in Fig. 15 wherein the full line representation of the pivot indicates its position and the consequent tensioning of the spring bearings when the breaker is closed. Therefore, it will be readily apparent that the compressed bearings tend to urge the pivot screw i2 in an upward direction, viewing Figs. 14 and 15, for resiliently biasing the movable contact member 243 upwardly in order to provide the desired contact pressure for the contacts 20 and 22.

Pursuant to another feature of the present invention, provision is made for wiping the companion contacts in order to remove any oxidized film which may have formed thereon, which film would tend to offer resistance to the flow of current through said contacts. In this connection it will be understood that the centers of each of the spring bearings 96 and 98 are free to rotate or move laterally within the respective openings 90 and 94 in the casing parts, as will be readily understood. Therefore, it will be apparent that in addition to the vertical bodily movement of the pivot screw 12 from the position thereof illustrated in Fig. 17 to the position thereof illustrated in Fig. 14, the pivot screw is also mounted for limited bodily movement in a lateral direction as indicated by the arrow 104B. in Fig. 13 and the arrow [85 in Fig. 15. More particularly, in moving the handle 2613 from the position thereof illustrated in Fig. 16, to the full line position thereof illustrated in Fig. 13, in order to close the circuit breaker and to over-set the toggle constituted by the link 39B and the actuator 2 813, the handle passes through an intermediate position, illustrated in broken line in Fig. 13, at which position the toggle is at the point of being overset. As said intermediate position, the movable contact 2213 makes its initial contact with the stationary contact 2013, as illustrated in the broken line position thereof illustrated in Fig. 13. Continued movement of the handle B through said intermediate positions to its full line position in Fig. 13, to complete the over-setting of the toggle, creates a lateral component of force in the direction of the arrow MB or the arrow I05, which results in limited bodily movement of the movable contact member 245 in the direction of said arrows to cause the movable contact 22B, to slide along or wipe the abutting surface of the stationary contact 2013 and to position said movable contact in the full line position thereof illustrated in Fig. 13. Said wiping action, under the pressure or tension applied by the compressed bearings 96 and 98, tends to remove any film formed on the abutting surfaces of said contacts. It will be readily apparent that said lateral movement of the movable contact member 243 results in the lateral movement of the pivot screw 12 in the direction of the arrow [MB or I05 which movement is facilitated by the rotation or lateral movement of the centers of the spring bearings, as previously described.

In this connection, it will be understood that said wiping action of the companion contacts is also present in the embodiment illustrated in Fig. 1. In said embodiment it will be noted that the spring pivot 52, in addition to the previously described downward bowing thereof, is also movable at the central portion 52A thereof, on which the movable contact member it is mounted, in a lateral direction, as indicated by the arrow 64 in said figure, to provide for the limited bodily movement of said contact member in the direction of said arrow Hi l. In said figure, the broken line position of the handle 25 indicates the point in the handle movement at which initial contact is made between the companion contacts and at which point the toggle begins to be over-set, so that the movable contact 22 thereof will move from the initial broken line position thereof, to the full line position thereof.

Referring to Figs. 14 and 17, it will be noted that the opening 88 in the casing part I 813 is provided with a protective seal I which closes said opening after the pivot screw l2 has been adjusted to provide for the desired calibration of the circuit breaker, as described. A washer I08 is then inserted in the casing part HJB over said seal.

Referring now to Figs. 20 through 26 in detail,

there is illustrated another embodiment having a resilient pivot for the movable contact member of a circuit breaker. Pursuant to the present embodiment, the pivot H0 is constituted by a strip of sheet metal which is cupped, as illustrated in Fig. 22. The casing parts and [2C are provided with bearing apertures H2 and 1M, respectively, which are downwardly inclined, as best illustrated at H6 and H 8, respectively, in Fig. 24. The opposite ends of the pivot iii] are disposed in said bearing apertures and the outer marginal edge I20 of the strip, which forms the pivot l H), is keyed in the companion casing parts, as illustrated in Fig. 22. Fig. 24 illustrates the condition of the pivot strip Hii in the Off position of the circuit breaker, and Fig. 21 illustrates the condition thereof when the breaker is closed. From the foregoing, it will be apparent that the pivot strip I I0 is resiliently flexible in a direction at right angles to the plane of the abutting faces of contacts 20 and 22, respectively, as indicated of the arrow H5. More specifically, it will be understood that maximum compression of the pivot strip Hi3 is attained at the point in the movement of the handle 26 from the position illustrated thereof in Fig. 20, at which the toggle constituted by the link 30 and the actuator 28 is in alignment, with the various toggle centers forming a straight line. Continued movement of the handle 26 in a direction to over-set the toggle, so that the link 30 and the actuator 28 will assume over-set positions thereof illustrated in Fig. 20, results in a partial decrease in the bowing of flexing of the pivot strip Hi. However, it will be understood that said strip remains partially bowed in the over-set condition of the toggle, as illustrated in Fig. 21, and that said partial bowing of the strip is sufficient to urge the movable contact member 26$ in a direction to apply the desired contact pressure. In this connection it will be unders good that the portion 66C of the movable contact member 240', in which the pivotal strip 1 I0 is engaged will move downwardly from the position thereof illustrated in Figs. 24 and 25 to its position in Fig. 21, in response to the bowing of the pivot strip Ill] whereby the bowed pivot strip tends to urge the portion 660 in the opposite direction to apply the desired contact pressure.

Still another embodiment having a resilient pivot is illustrated in 27 through 36. In the present embodiment, the pivot, which extends through the movable contact member MD, is constituted by a non-resilient pin I which is mounted for limited bodily vertical movement in the elongated bearing recesses I22 and i2 5 provided in the companion casing parts [dB and !2D, respectively. In order to provide for resiliently biasing said pivot pin whereby the movable contact member 2413 will be resiliently urged in a direction to effect the desired contact pressure, provision is made for a spring member l2fi, best illustrated in Fig. 35. More particularly, it will be noted that the member H6 is provided with a base portion I28 having at one end thereof the upturned flange ltd and being provided at the other end thereof with the reflexed spring arms I32 and 53 5, respectively, the base portion 528 being slotted, as at I36 between said arms. In order to mount the spring member I26 in position to bias pivot pin lift for bodily movement in a direction to apply the desired contact pressure, the casing parts it?!) and MD are provided with confronting ledge portions ltd-438 below the bearing recesses thereof, as best illustrated in Figs. 28 and 31, to provide a seat for the spring member I26, whereby the companion arms l32 and I34 thereof straddle said movablecontact member and engage the pivot pin i2il at opposite sides thereof, as illustrated in Figs. 28 and 31. The casing is also provided with a shoulder Hill which is engaged of flange 39.

From the foregoing it will be apparent that when the handle moved from the Off position thereof illustrated in Fig. to the On position thereof illustrated in Fig. 2'7, to overset the toggle constituted by the link 30 and the actuator the previously described downward component of force resulting from the over-set toggle will tend to move the portion Bill) of the movable contact member, in which the pivot pin is mounted, downwardly from the position thereof illustrated in Fig. 31, which represents the open condition of the circuit breaker, to the position illustrated in Fig. 28, which represents the closed condition of the circuit breaker. It will be apparent that said movement of the movable contact member will cause the pivot pin H29 to move downwardly the elongated bearing apertures lit and 2 1, to flex or compress the companion spring arms $32 and 13 from the relaxed condition thereof illustrated in Fig. 30, to the compressed or tensioned position thereof illustrated in Fig. 27. Said tensioning of the spring arms will result in the resilient biasing of the movable contact member 241) in a direction to effect the desired contact pressure.

In order to provide the circuit breaker of Fig. 27' with the previously described contact wiping action, the elongated recesses 12?. and IM may be diagonally directed, in the manner as illustrated by the recess l22A in Fig. 32. Said Fig. 32 is similar to Fig. 29, but illustrates an elongated diagonal recess for obtaining lateral movement of the pivot pin lit in the direction of the arrow lil in Figs. 27 and 32, upon oversetting of the toggle, as previously described. It will be understood that with each casing part provided with a recess which is diagonally disposed, as indicated in Fig. 32, the movable contact member MD will be provided with limited lateral bodily movement in the direction of the arrow Ml in 2'7 to provide for the previously described contact wiping action.

The circuit breaker Fig. 2'? may also be provided with a pivot which has the additional function of calibrating the circuit breaker. In this connection, it will be noted as illustrated in Figs. 34 and 35, that the pivot pin i253 may be replaced with a screw type pivot I42, of the type illustrated and described in our co-pending U. S. Patent No. 2,842,509 and assigned to the assignee hereof. The pivot Hi2 is provided with a screw driver slotted end portion its, an intermediate threaded tapered portion M5 and an unthreaded bearing portion its at the other end thereof. It will be understood that the pivot screw hi2 will be threaded into a threaded aperture provided in the movable contact member 25D, which is similar to the aperture is provided with the lateral marginal edge opening as previously described in connection with the movable contact member MB of Fig. 13, and as illustrated at "58A and at iifiA in Fig. 35. From the foregoing, it will be understood that the tapering portion let is in threaded engagement in the pivot opening 'SSA and the bearing portion M8 is disposed in the recess 124 in casing part i213. In this connection, it will be understood also that the companion bearing aperture I22B extends completely through the casing part lilD for access to the screw head on the pivot member 3 52. Therefore, it will be apparent that as the tapering portion Me is screwed further into the pivot opening 18A, the portion of the movable contact member 26D on which the actuator 23 is mounted, will be moved in a counterclockwise direction, viewing Fig. 27, relative to the portion of said movable contact member on which the latch 38 is carried, to vary the amount of overlap of the end M of the actuator relative to the bi-metallic strip All, as previously described in connection with the circuit breaker illustrated in Fig. 13. After the desired calibration is achieved, the opening i228 may be closed by means of the washer I50 and the sealing compound H52.

In order to provide for resiliently biasing the pivot M2, for resiliently urging the movable contact member 261) to provide the desired contact pressure, the spring member its straddles movable contact ZSD, as previously described, so that the spring arms I32 and HM thereof engage the pivot M2 at both sides of the movable contact member, as illustrated in Fig. 35. It will be apparent that the spring arms E32 and when tensioned in the closed condition of the circuit breaker, act upon the pivot Hi2 in the same manner as upon the pivot I29 to provide the desired contact pressure.

Where the screw type pivot M2 is used in place 11 of the pivot pin 129, the calibrating aperture lilD in the movable contact member 26]) is omitted as the breaker is provided with the pcripheral recess SGA.

The subject matter of the present application is related to the subject matter of our copending continuing application Serial No. 367,324, filed July 10, 1953, and assigned to the assignee hereof.

While we have shown and described the preferred embodiments of our invention, it will be understood that various changes may be made in the present invention without departing from the underlying idea or principles of the invention within the scope of the appended claims.

Having thus described our invention, what we claim and desire to secure by Letters Patent, is:

1. In a circuit breaker having companion relatively movable contact members provided respectively with contacts which are engageable with and disengageable from each other for closing and opening the circuit breaker, at least one of said contact members being substantially rigid and pivotally movable in a substantial ly fixed path for engaging the contact thereof with and disengaging the same from said other contact, and means for moving said movable contact member to a substantially stationary position in which said companion contacts are in engagement; means providing resilient con" tact pressure in said stationary position of said movable contact member, comprising spring means located at the pivotal support of said movable contact member and exerting pressure thereon, while the latter is in said stationary position thereof, for resiliently pressing said contact of the movable contact member against the contact of the companion contact member, a casing in which said contact members and said mechanism are mounted, means in said casing providing elongated bearing recesses and said movable contact member having parts supported in said recesses, for providing said pivotal support for said movable contact member and for a limited bodily movement of the latter against the pressure of said spring means in the engaged condition of said contacts.

2. In a circuit breaker having companion relatively movable contact members provided respectively with contacts which are engageable with and disengageable from each other for closing and opening the circuit breaker, at least one of said contact members being substantially rigid and pivotally movable in a substantially fixed path for engaging the contact thereof with and disengaging the same from said other contact, and means f or moving said movable contact member to a substantially stationary position in which said companion contacts are in engagement; means providing resilient contact pressure in said stationary position of said movable contact mem' ber, comprising spring means located at the pivotal support of said movable contact member and exerting pressure thereon, while the latter is in said stationary position thereof, for resiliently pressing said contact of the movable contact member against the contact of the companion contact member, a casing in which said contact members and said mechanism are mounted, means in said casing providing elongated bearing recesses and said movable contact member having parts supported in said recesses, for providing said pivotal support for said movable contact member and for a limited bodily movement of the latter against the pressure of said spring 12 means in the engaged condition of said contacts, said elongated recesses having an angular direction in relation to the path of movement of the movable contact so that the face of the movable contact has a limited sliding engagement with the face of the other contact.

3. In an automatic circuit breaker having a casing, a movable contact member mounted for pivotal movement in said casing and provided with a contact engageable with a companion contact in abutting face-to-face relation therewith in the closed condition of the circuit breaker, and means for pivotally moving said movable contact member to engage said contact thereof with and to disengage it from said companion contact; means in said casing providing said pivotal mounting for said movable contact member, comprising pivotal bearing parts and spring biased means supporting said movable contact member in said bearing parts, said spring biased means acting on said movable contact member to press its contact yieldably against said companion contact in abutting face-to-face relation therewith when said movable contact member is pivotally moved to close the circuit breaker.

4. In a circuit breaker having a casing, a movable contact member mounted for pivotal movement in said casing and provided with a contact engageable with a companion contact in abutting face-to-face relation therewith in the closed condition of the circuit breaker, and means for pivotally moving said movable contact member to engage said contact thereof with and to disengage it from said companion contact; means in said casing providing said pivotal mounting for said movable contact member, comprising pivotal bearing parts and spring biased means supporting said movable contact member in said bearing parts, said spring biased means acting on said movable contact member to press its contact yieldably against said companion contact in abutting face-to-face relation therewith when said movable contact member is pivotally moved to close the circuit breaker, said spring biased means comprising a resiliently flexible member having opposite end portions thereof supported in said bearing parts.

5. In a circuit breaker having casing, a movable contact member mounted for pivotal movement in said casing and provided with a contact engageable with a companion contact in abutting face-to-face relation therewith in the closed condition of the circuit breaker, and means for pivotally moving said movable contact member to engage said contact thereof with and to disengage it from said companion contact; means in said casing providing said pivotal mounting for said movable contact member, comprising pivotal bearing parts and spring biased means supporting said movable contact member in said bearing parts, said spring biased means comprising a member disposed transversely of said movable contact member and supporting the latter and having end portions thereof disposed in said bear ing parts, said transversely disposed member being substantially rigid and having a limited bodily movement in said bearing parts, said spring biased means acting on said movable contact member to press its contact yieldably against said companion contact in abutting face-to-face relation therewith when said movable contact member is pivotally moved to close the circuit breaker.

6. In a circuit breaker having a casing, a mov able ontact member mounted for pivotal movement in said casing and provided with a contact engageable with a companion contact in abutting face-to-face relation therewith in the closed condition of the circuit breaker, and means for pivotally moving said movable contact member to engage said contact thereof with and to disengage it from said companion contact; means in said casing providing said pivotal mounting for said movable contact member, comprising pivotal bearing parts and spring biased means supporting said movable contact member in said bearing parts, said spring biased means comprising resilient means and a comparatively rigid member engaged by said resilient means and disposed transversely of said movable contact member for supporting the latter and having portions thereof disposed in said bearing parts, said resilient means comprising a member having a part supported by said bearing parts and a bifurcated resilient part engaging said portions of the rigid member at opposite sides of said movable contact member, said spring biased means acting on said movable contact member to press its contact yieldably against said companion contact in abutting face-to face relation therewith when said movable contact member is pivotally moved to close the circuit breaker.

7. In a circuit breaker having a casing, a movable contact member mounted for pivotal movement in said casing and provided with a contact engageable with a companion contact in abutting ia.cet-o-face relation therewith in the closed condition of the circuit breaker, and means for pivotally moving said movable contact member to engage said contact thereof with and to disengage it from said companion contact; means in said casing providing said pivotal mounting for said movable contact member, comprising pivotal bearing parts and spring biased means supporting said movable contact member in said bearing parts, said spring biased means comprising resilient means and a comparatively rigid member engaged by saidresilient means and disposed transversely of said movable contact member for supporting thereof disposed in said bearing parts, said resilient means comprising spiral springs disposed in and supported by said bearing parts and engaging said portions of said comparatively rigid member, said spring biased means acting on said movable contact member to press its contact yieldably against said companion contact in abutting faoe-to-faoe relation therewith when said movable contact member is pivotally moved to close the circuit breaker.

8. In a circuit breaker having a casing, a movable contact member mounted for pivotal movement in casing and provided with a contact engageable with a companion contact in abutting iace-todace relation therewith in the closed condition of the circuit breaker, and means for pivotally moving said movable contact member to engage said contact thereof with and to dis engage it from said companion contact; means in said casing providing said pivotal mounting for said movable contact member comprising pivotal bearing parts and spring biased means supporting said movable contact member in said bearing parts, said spring biased means comprising a helical coil spring extending transversely through said movable contact member for supporting the latter and having opposite end portions supported in said bearing parts, said spring biased means acting on said movable contact member to press its contact yieldably against the latter and having portions 1 14 said companion contact in abutting face-to-face relation therewith when said movable contact member is pivotally moved to close the circuit breaker.

9. In a circuit breaker having a casing, a movable contact member mounted for pivotal movement in said casing and provided with a. contact engageable with a companion contact in abutting face-to-face relation therewith in the closed condition of the circuit breaker, and means for pivotally moving said movable contact member to engage said contact thereof with and to disengage it from said companion contact; means in said casing providing said pivotal mounting for said movable contact member, comprising pivotal bearing parts and spring biased means supporting said movable contact member in said bearing parts, and said spring biased means comprising a flat resiliently flexible member extending transversely through said movable contact member for supporting the latter and having opposite end portions supported in said bearing parts, said spring biased means acting on said movable contact member to press its contact yieldably against said companion contact in abutting iace-to-face relation therewith when said movable contact member is pivotally moved to close the circuit breaker.

10. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, an actuating member carried by said movable member, a currentresponsive device for operatively connecting said actuating member releasably to said movable member for operating the latter except when said current-responsive device is disconnected from said actuating member, resilient pivot means for said movable member operable to exert con-- tact pressure between said companion contacts in the engaged condition thereof, said resilient pivot means comprising a pivot on which said movable member is mounted for pivotal movement thereof, and resilient means operable upon said pivot for effecting said contact pressure, and means including interengaging relatively adjustable parts of said pivot and said movable member, respectively, for adjusting the releasable connection between said actuating member and said current-responsive device, whereby to calibrate the circuit breaker for automatic opening thereof upon overload.

11. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, an actuating member carried by said movable member, a currentresponsive device for operatively connecting said actuating member releasably to said movable member for operating the latter except when said current-responsive device is disconnected from said actuating member, resilient pivot means for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient pivot means comprising a pivot on which said movable member is mounted for pivotal movement there of, and resilient means operable upon said pivot for efiecting said contact pressure, said movable member having an opening therethrough, said opening extending to an edge of said movable member, and. said pivot being a spindle having an axially tapering threaded part passing through said opening in threaded engagement with the wall of said opening, whereby turning of said spindle about its axis relatively to said movable member is effective to displace a part of the latter for adjusting the releasable connection between said actuating member and said currentresponsive device, whereby to calibrate the circuit breaker for automatic opening thereof upon overload.

12. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, an actuating member carried by said movable member, a currentresponsive device for operatively connecting said actuating member releasably to said movable member f r operating the latter except when said current-responsive device is disconnected from said actuating member, resilient pivot means for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient pivot means comprising a pivot on which said movable member is mounted for pivotal movement thereof, and resilient means operable upon said pivot for efiecting said contact pressure, said movable member having an opening therethrough, said opening extending to an edge of said movable member, and said pivot being a spindle having an axially tapering threaded part passing through said opening in threaded engagement with the wall of said opening, whereby turning of said spindle about its axis relatively to said movable member is eifective to displace a part or" the latter for adjusting the releasable connection between said actuating member and said current-responsive device, whereby to calibrate the circuit breaker for automatic opening thereof upon overload, said resilient means comprising a resilient mounting for said spindle to provide said spindle with limited movement transversely of the pivotal axis.

13. A circuit breaker comprising circuit breaker mechanism and a casing in which said mechanism is operatively mounted, said casing having laterally spaced Walls provided with aligned bearing portions, said mechanism comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movabl member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and a resilient mounting for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a resiliently flexible pivot on which said movable member is mounted, said flexible pivot being supported for pivotal movement by said bearing portions of the casing.

14. A circuit breaker comprising circuit breaker mechanism and a casing in which said mechanism is operatively mounted, said casing having laterally spaced walls provided with aligned bearing portions, said mechanism comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and a resilient mounting for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a resiliently flexible pivot on which said movable member is mounted, said flexible pivot being supported for pivotal movement by said bearing portions of the casing, said bearing portions providing for limited movement of the pivot ends, whereby to facilitate the flexing of the pivot between the ends thereof upon closing of the circuit breaker.

15. A circuit breaker comprising circuit breaker mechanism and a casing in which said mechanism is operatively mounted, said casing having laterally spaced walls provided with aligned bearing portions, said mechanism comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and a resilient mounting for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a spring wire pivot on which said movable member is mounted, the ends of said pivot being engaged in said bearing portions, respectively, and said bearing portions being formed to provide for limited movement of the pivot ends therein, whereby to facilitate the flexing of the pivot between the ends thereof upon closing of the circuit breaker.

16. A circuit breaker comprising circuit breaker mechanism and a casing in which said mechanism is operatively mounted, said casing having laterally spaced walls provided with aligned bearing portions, said mechanism comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and a resilient mounting for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a resiliently fl xible pivot on which said movable member is mounted, said flexible pivot being supported for pivotal movement of said bearing portions of the casing, said bearing portions providing for limited movement of the pivot ends, whereby to facilitate the flexing of the pivot between the ends thereof upon closing of the circuit breaker, each pivot end having a sleeve in the form of a truncated cone, said sleeves being disposed in said bearing portions, respectively, and said bearing portions having contours complementary to said sleeves.

17 A circuit breaker comprising circuit breaker mechanism and a casing in which said mech anism is operatively mounted, said casing hav- 17" ing laterallyspaced walls. provided with aligned bearing portion, said: mechanism comprising relatively movable companion contacts engageable with and disengageablev from each. other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means foractuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and a resilient mounting for said movable member operable. toexert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a pivot on which said movable member is mounted, said pivot being constituted. by. a

coiled spring member the ends of which are engaged in said bearing portions, respectively.

18. A. circuit breaker comprising circuit breaker'mechanism and a casing in which said mechanism is operatively mounted, said casing having laterally spaced walls provided with aligned bearing. portions, said mechanism comprising relatively movable companion contacts engageable with and disengageable from each other for closing. and opening the circuit breaker, a movable'member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping oi the breaker, and a resilient mounting for said movable member operable toexert contact pressure between said companion contacts in the engaged condition thereof, said resilient moun ing comprising a pivot on which said movable member is mounted, said pivot being constituted by a coiled springmember the ends of which are engaged in saidbearing portions, respectively, said bearing portions having surface portions inclined in the direction of'the flexing of said pivot.

19. A circuit breaker comprising circuit breaker mechanism and acasing in whichsaidmecha nism is operatively mounted, said casing having laterally spaced walls provided with aligned bearing portions, said mechanism comprising relatively movable companion contacts engageable with and disengageable' from each other for closing and opening the circuit breaker, a mov-- able member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of' the breaker, and a resilient mounting for saidmovable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a pivot on which said movable member is mounted, said pivot comprising a cupped'strip of metal, the ends of said' strip being substantially securely retained in said bearing portions to facilitate the flexing thereof between said ends upon closing or" the circuit breaker.

20; A circuit breaker comprising circuit breakermechanism-and a casing in which said mechanism is operativelymounted, said casing having laterally spaced" walls provided with aligned'bear ing portions, said mechanism comprising relatively movable companion contacts engageablewith and'diseng-ageable from each other for clos-' ing and opening the circuit breaker, a movable ill able member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a substantially rigid; pivot for said movable member, said pivot being mounted in said bearing portions for limited movement thereof transversely of the pivotal axis, and resilient means operable upon said pivot to effect said contact pressure.

21. A circuit breaker comprising circuit breaker mechanism and a casing in which said mechanism is operatively mounted, said casing having 1 laterally spaced walls provided'with aligned bearing portions, said mechanism comprising relatively movable companion contacts engageable with and'disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable mem ber operable upon overload to release said-movable" member for automatic tripping of the breaker, and a resilient mounting for said mov able member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a substantially rigid pivot for said movable member, said pivot being mounted in said bearing portions for limited movement thereof transversely of the pivotal axis, and resilient means operable upon said pivot to effect said contact pressure, said resilient means comprising resilient members contained in said bearing portions, respectively.

22. A circuit breaker comprising circuit breaker mechanism and a casing in which said mechanism is operatively mounted, said casing having laterally spaced wallsprovided with aligned'bear ingv portions, said mechanism comprising relatively movable companion contacts engageable" with and disengageable from each other for clos ing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means: including latching means for said movable momber operableupon overload to release said movable member for automatic tripping of the transversely of the pivotal axis, and resilient means operable uponsaid pivot to effect saidcontact pressure, said resilient means comprising a helically coiled spring member in each bearing portion for'resiliently mountingthe pivot portion" in-the companion bearing portion.

23. In a'circuit breaker having a'casing, a movable contact member mounted for pivotalmove-- merit in said casing and provided with a contact engageable with acompanion contact in abutting face-to-face relationtherewith in'the closed condition'of the circuit breaker, and means for ply-- otally moving said movable contact member to engage said contact thereof with and to disengage it from said companion contact; means in said casing providing said pivotal mounting for said movable contact member, comprising pivotal bearing parts and spring biased means supporting said movable contact member in said bearing parts, said spring biased means comprising a spiral spring member extending transversely through said movable contact member for supporting the latter and having opposite end portions supported in said bearing parts, said spring biased means acting on said movable contact member to press its contact yieldably against said companion contact in abutting face-to-face relation therewith when said movable contact member is pivotally moved to close the circuit breaker, said bearing parts being inclined in the direction of flexing of said spring member.

24. In a circuit breaker having a stationary contact, a pivotally movable contact member having a contact engageable with and disengageable from said stationary contact, and means for actuating said movable member to engage and disengage said companion contacts, that improvement which comprises the provision of a pivot mounting for said movable member for said movement thereof whereby it has provision for limited bodily movement in a direction parallel to the plane of the engaged contact faces to provide for a limited sliding movement of the movable contact along the face of the stationary contact upon engagement and disengagement of said contacts.

25. In a circuit breaker having a stationary contact, a pivotally movable contact member having a contact engageable with and disengageable from said stationary contact, a currentresponsive latch carried by said movable contact member, and an actuator pivotally mounted on said contact member and operatively connected thereto, under the control of said latch, for closing the circuit breaker, that improvement which comprises the provision of a pivot mounting for said movable member for said movement thereof whereby it has provision for limited bodily movement in a direction parallel to the plane of the engaged contact faces to provide for a limited sliding movement of the movable contact along the face of the stationary contact upon engagement and disengagement of said contacts.

26. In a circuit breaker having a stationary contact, a pivotally movable contact member having a contact engageable with and disengageable from said stationary contact, a current-responsive latch carried by said movable contact member, and an actuator pivotally mounted on said contact member and operatively connected thereto, under the control of said latch, for closing the circuit breaker, that improvement which comprises the provision of a pivot mounting for said movable member for said movement thereof whereby it has provision for limited bodily movement in a direction parallel to the plane of the engaged contact faces to provide for a limited sliding movement of the movable contact along the face of the stationary contact upon engagement and disengagement of said contacts, a manually operable handle movable to different positions for operating the movable contact member to open and close the circuit breaker in the manual operation thereof, and a connection between said handle and actuator which prevents relative pivotal movement between said actuator and the movable contact member when the 2b handle is in circuitclosing a on and the ac-' tuator is latched to said movable contact member, said handle and said connection constituting a toggle operative upon said initial engagement of said contacts to urge said pivot mounting in said direction.

27. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and a resilient mounting for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting additionally providing for limited bodily movement of said movable member in a direction parallel to the plane of the engaged contact faces to provide for a limited sliding movement of said one contact along the face of the other contact upon initial engagement of said contacts.

28. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and resilient pivot means for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said pivot means additionally providing for limited bodily movement of said movable member in a direction parallel to the plane of the engaged contact faces to provide for a limited sliding movement of said one contact along the face of the other contact upon initial engagement of said contacts.

29. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said actuating means including latching means operable upon overload to release said movable member for automatic tripping of the breaker, and flexible pivot means mounting said movable member for limited bodily movement in a direction parallel to the plane of the engaged contact faces in response to the actuation of said movable member to engage said companion contacts, whereby to provide for a limited sliding movement of the movable contact along the face of the stationary contact upon engagement of said contacts.

30. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said actuating means including latching means operable upon overload to release said movable member for automatic tripping of the breaker, and means mounting said movable member for limited bodily movement in a direction arallel to the plane of the engaged contact faces in response to the actuation of said movable member to engage said companion contacts, whereby to provide for a limited sliding movement of the movable contact along the face of the stationary contact upon engagement of said contacts, said. mounting means additionally providing for limited bodily movement of said movable member in a direction transversely of said first mentioned direction whereby to provide for proper contact pressure between said contacts in the closed condition of said circuit breaker.

31. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said actuating means including latching means operable upon overload to release said movable member for automatic tripping of the breaker, and means mounting said movable member for limited bodily movement in a direction parallel to the plane of the engaged contact faces in response to the actuation of said movable member to engage said companion contacts, whereby to provide for a limited sliding movement of the movable contact along the face of the stationary contact upon engagement of said contacts, said mounting means additionally providing for limited bodily movement of said movable member in a direction transversely of said first mentioned direction whereby to provide for proper contact pressure between said contacts in the closed condition of said circuit breaker, said mounting means comprising a pivot for said movable member, said pivot being flexible in both of said directions.

32. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said actuating means including latching means operable upon overload to release said movable member for automatic tripping of the breaker, and means mounting said movable member for limited bodily movement in a direction parallel to the plane of the engaged contact faces in response to the actuation of said movable member to engage said companion contacts, whereby to provide for a limited sliding movement of the movable contact along the face of the stationary contact upon engagement of said contacts, said mounting means additionally providing for limited bodily movement of said movable member in a direction transversely of said first mentioned direction whereby to provide for proper contact pressure between said contacts in the closed condition of said circuit breaker, said mounting means comprising a pivot for said movable member, and resilient bearing means for said pivot whereby said pivot is mounted for limited bodily movement in both of said directions.

33. In a circuit breaker having companion relatively movable contact members provided respectively with contacts which are engageable with and disengageable from each other for closing and opening the circuit breaker, at least" one of said contact members being substantially rigid and pivotally movable in a substantially fixed path for engaging the contact thereof with and disengaging the same from said other contact, and means for moving said movable contact member to a substantially stationary position in which said companion contacts are in engagement; means providing resilient contact pressure in said stationary position of said movable contact member, comprising spring means located at the pivotal support of said movable contact member and exerting pressure thereon, while the latter is in said stationary position thereof, for resiliently pressing said contact of the movable contact member against the contact of the companion contact member, said contact moving means comprising a toggle mechanism operatively connected to said movable contact member and held in overset condition when said movable contact member is in said stationary, contactengaged position thereof, circuit-current responsive means for releasing said movable contact member from said operative connection of said toggle mechanism therewith, and spring means for moving said movable contact member to opencircuit position upon said release of said movable contact member, said-contacts having a face-toface abutting engagement in the closed condition of the circuit breaker and said spring pivot means having provision for a limited sliding movement of said movable contact in engagement withsaid other contact during the initial part of the move ment of said movable contact member to circuitopening position.

34. In an automatic circuit breaker having companion relatively movable contact members provided with contacts, respectively, engageable s with and disengageable from each other for closing and opening the breaker, at least one of said contact members being substantially rigid and pivotally movable in a substantially fixed path; means for providing resilient contact pressure between said contacts when the latter are engaged with each other, said means comprising a resiliently movable mounting between the opposite ends of said movable contact member for supporting the latter for said pivotal movement thereof and for providing resilient contact pressure between said contacts when the latter are engaged.

35. In an automatic circuit breaker having companion relatively movable contact members provided with contacts, respecitvely, engageable with and disengageable from each other for closing and opening the breaker, both of said contact members being substantially rigid and at least one of said contact members being pivotally movable in a substantially fixed path; means for providing resilient contact pressure between said contacts when the latter are engaged with eachother, said means comprising a resiliently movable mounting between the opposite ends of said movable contact member for supporting the latter for said pivotal movement thereof and for providing resilient contact pressure between said contacts when the latter are engaged, said movable contact member being yieldably movable against said resilient bias, in the engaged condition of said contacts in the final part of the movement of said movable contact member to contact engaging position.

36. In an automatic circuit breaker having a stationary contact, a pivotally movable contact member having a contact engageable with and disengageable from said stationary contact, a current responsive latch carried by said movable contact member, and an actuator pivotally mounted on said contactmember and operatively connected thereto, under the control of said latch, for closing the circuit breaker, that improvement which comprises the provision of pivot means for said movable contact member for said pivotal movement thereof, said pivot means being di posed between said movable contact and said actuator and providing for limited bodily movement of said movable contact member while the actuator is latched thereto, whereby to provide for proper contact pressure between said contacts in the closed condition of the circuit breaker, and compression spring means for disengaging said contacts in the unlatched condition thereof.

37. In an automatic circuit breaker having companion relatively movable contact members provided respectively with contacts which are engageable with and disengageable from each other for closing and opening the circuit breaker, at least one of said contact members being substantially rigid and supported between the opposite ends thereof for pivotal movement in a substantially fixed path for engaging the contact thereof with and disengaging the same from said other contact, and means for moving said movable contact member to a substantially stationary.

position in which said companion contacts are in engagement; means providing resilient contact pressure in said stationary position of said mcv-- able contact member, comprising spring means located at the pivotal support of said movable contact member and exerting pressure thereon, while the latter is in said stationary position thereof, for resiliently pressing said contact of the movable contact member against the contact of the companion contact member.

38. In an automatic circuit breaker having companion relatively movable contact members provided respectively with contacts which are engageable with and disengageable from each other for closing and opening the circuit breaker, at least one of said contact members being sub stantially rigid and pivotally movable in a substantially fixed path for engaging the contact thereof with and disengaging the same from said other contact, and means for moving said movable contact member to a substantially stationary position in which said companion contacts are in engagement; means providing resilient contact pressure in said stationary position of said movable contact member, comprising spring means located at the pivotal support of said movable contact member and exerting pressure thereon, while the latter is in said stationary position thereof, for resiliently pressing said contact of the movable contact member against the contact of the companion contact member, said contact moving means comprising a toggle mechanism operatively connected to said movable contact member and held in overset condition when said movable contact member is in said stationary, contact-engaged position thereof, said pivotal support being intermediate the contact of said movable contact member and said operative connection thereto, circuit-current responsive means for releasing said movable contact member from said operative connection of said toggle mechanism therewith, and spring means for moving said movable contact member to open-circuit position upon said release of said movable contact member.

39. In a circuit breaker having a stationary contact, a pivotally movable contact member having a contact engageable with and disengageable from said stationary contact, a currentresponsive latch carried by said movable contact member, and an actuator pivotally mounted on said contact member and operatively connected thereto, under the control of said latch, for closing the circuit breaker, that improvement which comprises the provision of a pivot mounting for said movable member for said movement thereof whereby it has provision for limited bodily movement in a direction parallel to the plane of the engaged contact faces to provide for a limited sliding movement of the movable contact along the face of the stationary contact upon engagement and disengagement of said contacts, said pivot :icunting comprising a substantially rigid pivot and resilient bearing means therefor.

40. A circuit breaker comprising circuit breaker mechanism and a cas ng in which said mechanism is operatively mounted, said casing having laterally spaced walls provided with aligned bearing portions, said mechanism comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and a resilient mounting for said movable member operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a substantially rigid pivot for said movable member, said pivot being mounted in said bearing portions for limited movement thereof transversely of the pivotal axis and resilient means operable upon said pivot to effect said contact pressure, said resilient means being a resilient member having laterally spaced portions engaging said pivot at opposite sides of said movable member, respectively.

41. A circuit breaker comprising circuit breaker mechanism and a casing in which said mechanism is operatively mounted, said casing having laterally spaced walls provided with aligned bearing portions, said mechanism comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said means including latching means for said movable member operable upon overload to release said movable member for automatic tripping of the breaker, and a resilient mounting for said movable meznber operable to exert contact pressure between said companion contacts in the engaged condition thereof, said resilient mounting comprising a pivot on which said movable member is mounted, said pivot comprising a cupped strip of metal, the ends of said strip being substantially securely retained in said bearing portions to facilitate the flexing thereof between said ends,

upon closing of the circuit breaker, and said bearing portions being inclined in the direction of said flexing.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,150,012 Von Hoorn Mar. 7, 1939 2,209,351 Sachs July 30, 1940 2,308,303 Randall Jan. 12, 1943 

